Controller Design Based on a Synchronous Error Compensator for Wheeled Cross-coupled Systems

This study proposes a method for operating wheeled cross-coupled systems. Wheeled cross-coupled systems are more sensitive to disturbances than other cross-coupled systems. When the slip phenomenon occurs in wheels, it causes synchronous errors between axles, resulting in differences in the controller outputs of the two axles. In the worst case, the two axles can end up competing. To solve this problem, this study introduces base controllers to each axle using a discrete-time variable structure control system with a decoupled disturbance compensator and an auxiliary controller, called a synchronous error compensator (SEC), to minimize synchronous errors arising from differences in the states of the two axles. Experiments are conducted on a verification system with a similar form of overhead hoist transfer (OHT) to demonstrate the effectiveness of the proposed method. Results reveal that the SEC generates control commands to make the control inputs (current command) and state variables (velocity feedback) of the two axles similar.